Dictograph intercommunicating telephone system.



W. P. ANDRICK.

DICTOGRAPH INTERCOMMUNICATING TELEPHONE SYSTEM.

APPLICATION FILED OCT. 10. 1913.

1 1 60, 1 25 Patented Nov. 1 6, 1915.

2 SHEETS--SHEET 2.

s Lg WITNESSES INVENTOR By fl 4-, M

' ATTORNEY W. P. ANDRICK.

D|CTOGRAPH INTERCOMMUNICATING TELEPHONE SYSTEM.

APPLICATION FILED OCT. 10. 1913.

1,16Q,125. I Patented Nov. 16, 1915.

2 SHEETS-SHEET l.

WITNESSES I MENTOR 8 BY W7- ATTORNEY UNITED STATES PATENT orrion.

wnmaacn 2mm mmcx, or rename, new that, ASSIGNOR 'ro GENERAL ncous'nc comm, or JAMAICA. m roan. A eonroanrxon or new roman.

DIGTOGRAPE IIIIV'JtIElIM-{QMBUZQIOATIING TELEPHONE SYSTEM.

Specification otLetters Patent.

Patented Nov. 16, 1915.

Application filed October 10, 1918. Serial No. 794,501.

To all whom it may concern:

Be it known that I, Wanmca PFAU AN- nmcK, citizen of the United States, and resident of Jamaica, in the county of Queens and State of New York, have invented certain new and useful Improvements in Dictograph Intereommunicatin Telephone Systoms, of which the following is a specification.

to I This invention relates to a telephone system involving one or more stations, adapted to be made part of an intercommumcatmg system, and also one or more additional stations, hereinafter termed master stations,

which are distinguished by the fact that they have sensitive transmitters and loud speaking receivers, and a private or individual line connection to, every other station with which they may be connected. This sort of system is adapted to factories and business purposes, where there are a few administrative heads, and many subordinate departments. The subordinate departments are satisfied by the ordinary intercommunicating station, without sensitive and loud speaking ins ruments, and in many cases without secrecy, but the administrative heads require a better service, afforded by the sensitive and administrative head or master station able.

to call any other station,-particularly the subordinate stations, even if the latter are talln'ng administrative head might be obliged to wait for the termination of some relatively unimportant conversation. It is, of course, also evident that the master'stations should not be called by any accidental circumstances, for example, as when one sub-station calls another. In systems of this class combina-' tions of circuits sometimes occur which are apt m cases to, send signaling currents among themselves. Otherwise, the

through paths different from the normal ones intended, and means must be rovided to avoid any accidental or unintentional signaling of any station in this way. Also accidental talking circuits must be vigorously guarded against, on account of secrecy, as there must be no improper electrical connec tions during talking. I

A further cause of non-secrecy in telephone systems arises from what is known as crosstalk which is the result of induction between circuits which are not actually hysical-ly connected with one another.

his may happen also by reason of the inability of retardation coils to prevent telephonic currents'being transmitted where the sensitive instruments of a master station are involved. Accordingly these effects must be guarded against in addition to the eflects of the accidental direct branch circuits or connections. Moreover, the connection of each master station with the stations of the intercommunicating system should not interfere with any result or practice already existing in simple combinations of master'or other stations, such for example as disclosed in U. S. Patents No. 843,186 and 927,230. It isthe object of the present invention to provide an improved telephone system satisfying all the foregoing requirements.

In the drawings, Figure 1 is a diagrammatic view showing two master stations and three stations of an intercommunicating system, two of the intercommunicating stations being adapted for communication to the master stations. Fig. 2 is a diagrammatic view showing a single master station and three intercommunicating stations, two of which are adapted for communication to the master station, this modification however differing from that of Fig. 1 in the fact that code signaling will be used where more than one master station is connected.

Referrin to Fig. 1, A and A denote master stations and X, Y and Z'substati0ns or intercommunicating stations.

The master stations have a plurality of keys 1, 2 and 3, respectively, controlling individual line connections to the other stations and to each other. Key 1 controls a; line connection to the other master station, while keys 2 and 3 control connectionsEto;

the sub-stations X and Y. In addition tov used. The master stations further have a g sensitive transmitter "4 and a loud speaking receiver 8, and also an ordinary receiver 9 may be provided. There is also'a talking battery 10 and a ringing battery 11-, although the latter may be dispensed with it 5 desired, a suitable tap being provided to the ringing battery of the intercommunicating lines.

ceiver 9.

go The intercommunicating stations each have a sensitive transmitter 13, a receiver 14, retardation coils 15 and an audible signal 16 which may be generally 'referred'to as the station instruments. There are also keys 17 and 17 or known equivalents therefor, governing the connections to the other intercommunicating stations and the master station. The stations furthermore have visual signals 18, in the practical construction so illustrated, in Fig. 1 corresponding in numher at each station to the number of master stations of the system with ,Whichthat station is. connected. There is also a switch" book 12 and a ringing key 20' ateach 'substation.

In the best constructions embodying the invention each sub-station has a relay 21, the purpose of which is to connect the audible signal across the battery when a master station calls a sub-station.

The various circuits can best .bedescribed by tracing them for the various conditions which occur in practice, for example 1. When one sub-station calls another.

2. When, the second station answering, telephonic communication takes place. 7

3. When one master station calls another.

et-LWhen, the master station answering, conyer'sation takes place.

5. When a master station .calls, a sub-. station. 7

6. When, the-'sub-station answering, conversation takes place.

tion.

the conversation takes place. This isthe same as No. 6.

9. When a master station calls a busy su station.

10. When a ter-station.

. The foregoing are the main ordinary cirsub-station calls a busy mascuits established and used in the system, correspondingto what may be termed normal tardation coils.

7. When a sub-station calls a master Sta aaaoaae traffic conditions. In addition to these circuits, many connections exist in the shape of branches from the circuits already traced,

through which additional or branch circuits might occur were it not for the fact that in every such case interruptions have been provided which prevent any harmful effects on the working of the system.

Taking up now the various electrical circuits, in-the order otthe numbered para-. graphs just above given, the circuits when one sub-station calls another, for example when X calls Y are as follows z-Negatwe ringing battery R, wire Z, wire 1 wire l",

contacts of ringing key 20, wire 1, wire Z,

contacts of key 17, wire Z, wire I, wire 1 switch hook 12, signal 16, wire 1",, wire l", 24"is a switch hook controlling thereback to positive battery B. "As a result of this call station Y removes receiver'from'" the hook and telephonic circuits are estab- ,lished. as follows:--Battery T, wire m,

wire m retardation coil 15, wire m wire other ceiver 14, wire-m, contacts of key 17,-wire 'm, contacts of key 17, wire m, contacts of key 17", wire m, transmitter 13,'re-

m through a contact of the othermaster key 17 wire m, switch hook 12, wire m retardation coil 15, wire m, back to battery T. This circuit serves to bridge the telephone transmitter, and the telephone receiver at station X across the terminals of the talking battery through intervening re- 1 potential in this part of the circuit which may be impressed on the line to station Y This results in a varying i contacts of operated key 17 wire n line 01?,

wiren line a, contact of key 17 wire 11., contact of the other key 17, wire 71., transmitter 1%, receiver 14, wire 11.", contact of key 17', wire a, contact of the other key 17'. wire n, switch book 12, wire Z line wire 2, wire Z, contact of key 17, wire Z, wire I, contact of key 20, wire 11., wire-n switch hook 12,;wire m", contact of key 17', wire on, contact of other key 17 wire m", back to receiver-14. The current for the conversatlon from Y to X is supplied to the transmitter and receiverat station Y in exactly the same manner as already described for station X. The actual telephonic circuit ust referred to'is of course equally efiecs I tive in both directions. 8. When, the master station answering,-

It will next be necessary to consider the circuits when one master station calls another. f This calling of one master station byanother may take place in either of two ways. If the second master station is only a short distance away the ringing may be action A calls station A, this may be done by displacing talking key l. A ringing cirme ias cuit is established as follows :Battery 10, wire 0, receiver 8, wire 0 contact of key 1, wire 0 contact of key 1 at station A, wire 0, signal 4, wire 0, .wire 0, wire Z wire a", wire 0, back to battery 10. It will be observed that this circuit includes the signal at the called station. It however includes some resistance and has a lower voltage than is desirable for calls to remote stations. I An alternative calling circuit is as follows Battery 11, wire '0 wire 72, ringing key 6, wire 0 contacts of key 1 at station A wire 0, signal 4, wire a", wire 0, wire 1 wire 0, wire 0 back to battery 11.

The called station responds by displacing the indicated key and talking'circuits are established as follows :---Battery 10 at station A, wire 0, receiver 8, contact of switch hook, wire 0 contact of key-1 of station A, wire 0, contact of key 1 at station A, wire [2 transmitter 7, wire p contact of key 1, wire 1;, wire 0, wire 0", wlre 2, wire 0', wire 0 back to battery 10. This circuit 1ncludes the receiver of station A, and the transmitter at station A, and is effective for conversation in one direction. For conversation in the opposite direction the circuit is as follows :Battery 10 at station A wire q wire 9 receiver-8, contact of switch hook, wire 9 contact of key 1, wire 9, contact of key 1 at station A, wire g transmitter 7, wire 9, contact of key 1, wire 9", wire 0', wire I, wire 0, back to battery 10. This circuit includes the transmitter at station A the receiver at station A and provides for conversation from A to A. It will be observed that the talking circuits from master station to master station are dictograiph circuits.

It will next be necessary to consider the conditions when a master station calls a sub-station. Assuming that master station A calls sub-station X, the calling circuit is as follows Battery 10, wire 0, receiver 8, switch hook, wire 0 wire 1', contact of operated key 2, wire 1, contact of key 17', lamp 18, wire 1', relay 21, wire r, wire 1*, negative side of battery R through the battery to wire I, wire 0, wire a battery 10. This circuit provides for the illustration of the electric lamp or other type of visual signal 18, and the operation of the relay, but withoutimposing an undue potential on the transmitter and receiver of the talking circuit when the latter circuit is completed.

receiver 8, switch hook, wire 0 wire 1',

contact of key 2, wire r, contact of key 17', wire m, contact of the other key 17, wire m, transmitter 13, wire wire t contact contact of .key 17 wire t wire 1*, wire 0',

wire 0 back to battery 10.

When a sub-station calls a master station the circuit is as follows:Battery 11, wire 0", wire 0, wire Z wire t contact of key. 17 wire t wire receiver 14, wire m, contact of key 17, wire m contact of other key 17", wire u, contact of key 2 at master station A, wire '0 signal 4, wire o wire '0 back to battery 11. This circuit effects the selective operation of the signal at the called master station which signal responds by displacing the selected key. The conversation takes place through a circuit already traced in connection with the calling of a sub-station by a master-station. This provides for all conditions of'practice, except the conditions when a called line is busy. Assuming that the master station calls a busy substation, the circuits are as follows :Battery 10, wire 0 receiver 8, wire 0 wire 1' contact of key 2, wire 1' contact of key 17', signal lamp 18, wire 7' relay 21, wire 1'", wire 1', battery R wire I, wlre 0 Wire 0 back to battery 10. This circuit therefore notifies the busy substation of the call by the illumination of the signal lamp. The sub-station is thereby notified, as is desirable, but the disturbance of the buzzer or the audible signal is avoided, because the circuit through the audible signal can be completed only when the receiver is on the hook.

Finally, the conditions mav be considered when a sub-station calls a busy master station. Inasmuch as the busy master station will of course be connected by another key and line than that of the new calling station,.it follows that key and signal conditions are presented similar to those already traced whena sub-station calls a master station. The masters visual signal is therefore operated, but the master is provided with a switch 25 by which he may cut ofi" his audiblesignal at any time if this is desirable.

In Fig. 2 substantially the same circuits are illustrated as already shown and described in connection with Fig. 1, except that in place of the signal lamps 18 andrelay 21, an audible signal 26 is used. [This of course limits the number of masterbe adopted in order that the sub-station may respectively containing the telephonic in- .50

know which master station calls.

It will be observed from the foregoing description that while the sub-stations are joined by an intercommunicating system having the simplicity'and directness which characterizes such a system, that on the other hand the master stations. may have sensitive transmitters and loud speaking receivers, with circuits kept separate and .dis-

tinct, as is required with what is known as a dictograph system. The general requirements of a dictograph system are pointed out in United States Letters Patent Nos. 844,635, 875,081, 843 186 and 927,230. It is sufiicient to mention for the purpose of the present case, that the conversation at the master station should not be returned at the loudspeaking receiver of the same station, and furthermore the feature of secrecy, where a master station is involved, should be preserved. The minimum of at- 'tention. should be "required on the part of the master station operator to rules and details of usage. These conditions should be present, not only'when one master station is {talking to another, but, also when any master station is talking to a sub-station. In view of the fact that each master station has its own battery while only a common battery is provided for-the sub-stations, and

also in. view of the foregoing requirements,"

the dict-ograph circuits are of somewhat different character when a master station is talking to a sub-station from that when two master stations are talking to one another. When two masterstations are talking to one another it will be observed that two batteries supply current-for the communication, the same being in the legs of the three wire circuit including the receivers of the respective ma'ster stations'where the batteries are located. On the other hand, when a master station is talking to a sub-station only one "battery furnishes current for the connection, .the s'ame' being' inthe third wire ofthe three wire-connection, the other wires struments of" both stations.- lathe last mentioned casefthis third wire is tapped into. the circuit of the sub-station at a point between the. transmitter and receiver thereof. -When, however, the sub-stations are talking with; one another this tap 1s ldle,

the,,circuitsthereof being opened at the keys 17'; The minimum of trouble of opera-tion providedffor the master stations 3 which is obviously. a desirable feature. A master station call'sjjasub-station by the displacement of a talking key, and this calling circuit is automatically terminated when the sub-station answers. Furthermore, the mas- E *ter' :stationis not called upon to closely bear in. mind the returning of the talking key to normal position, because whenever this is not done, the sub-station is again continuously called. Being called, the sub-station will of course answer, and the answer will be audibly heard at the master station, thereby automatically reminding the masterstation to return the displaced .key to normal position. In this wavthe system is automatically kept in normalcondition without the necessity of imposing any rules or discipline on the master stations.

While the invention has been particularly described with keys at the master stations, and keys have been referred to in certain of the appended claims, this is merely for the purposes of clear and convenient designation, for it is obvious that the same results can be secured by the use of jacks instead of keys, the jacks serving the same functions as the keys in controlling a plurality of cir cuits by the single actuation ofa prescribed art.

It will further be obvious that other adaptations are readily possible, within the skill of an ordinary telephone mechanic, and

falling within the spirit and scope of the invention.

What is claimed is 1. In a telephone system having a plu rality ofmaster stations and a plurality of sub-stations, three wirecircuits extending from said master stations to the sub-stations and also to the other master stations, means for'including the transmitter and receiver in a master station directly in two wires of any of said three wire connections, and a battery in the third wire thereof when talking to any sub-station, and means for changing said circuits to put the battery in a c'ii'cuit wire including one of said telephone instruments, when talking to another transmitter and the receiver at the respective master stations. I

3. Ina telephone system, a plurality of substations, a master station, and connecting lines between the sub-stations, a three wire.

circuit extending from the master station to the sub-stations, and means for simultaneously connecting the two wires of said three wire circuit- -to the sub-station instruments, the third wire being tapped into circuit between the instruments, and eliminating all calling circuits between the talking keys of the master stations and talking circuits between the talking keys of the several stations, said talking circuits and calling circuits from a master station being closed simultaneously, each of the talking circuits from a sub-station being controlled by each of the talking keys at that station corre sponding to a master station.

15. In an intercommunicating telephone system, a plurality of sub-stations ancl a plurality of master stations, a plurality of talking keys at each station, one for each station of the system, a separate calling key at each sub-station, calling circuits between the tail;- in and calling keys of a sub-station an& the talking keys of the master stations, other calling circuits between the talking keys of the master stations and talking circuits between the talking keys of the several stations, said talking circuits and calling circuits from a master station being close& simultaneously, each of the talking circuits from a sub-station other than those leafling to a master station being opened upon the actuation of the talking key at the substation corresponding to said master station. Signefi at Jamaica, in the county oi Queens and State of New York, this 8th day of @ctoher, A. D. 1913.

WALLACE PL AU ANDRICK. Witnesses:

Amman W. Pnoc'ron, RAY Lava.

other connections from said instruments at such sub-station.

4. In a telephone system, a plurality of sub-stations, a master station, having a battery, and connecting lines between the substations, a three wire circuit extending from the master station to the sub-stations, and means for simultaneously connecting two wires of said three wire circuit to the substation instruments, the third wire beingtapped into circuit between the instruments, and including said battery, and eliminating all other connections from said instruments at such sub-station.

5. In a telephone system, a pluralit of master stations, a plurality of substat1ons, a source of current for the master stations, a three wire circuit extending therefrom to each of the sub-stations, a connecting system havin a common battery joining the various su -statious, 'and means for simultaneously connecting the instruments of any sub-station with the three wires to a master station, and eliminating all other connections to the other sub-stations, and to the common battery.

6. In a tale hone system, a master station, a lurality oi substations each having visnal signals and an audible signal, means for calling said sub-stations from the master station, and means operating both audible and visual signalsat the sub-station when the said sub-station is not in use, and said Iigisual signal exclusively when the station is 7. In a tele hone system,'a master station, a plurality o sub-stations, visual and audible'signals at both the master station and sub-stations, means for operating the visual signals at the respective stations under all conditions, and means for preventing the operation of the audible si als at the respective stations when the atter are busy.

8. In a telephone system, a plurality of sub-stations, a master station, three wire circuits joining the master station with the" said sub-stations, an inter-communicating system joining the said sub-stations together, means operated. by the single displacement of a talkin key at the master station for calling a su -station, and means for terminating said calling circuit when the said sub-station answers. I

9., In a tele hone system, a master station, a plurality of sub-stations, a loud speaking receiver and sensitive transmitter at the master station, and means for calling the sub-station by the single displacement of a talking key at the master station controlled by the removal of the receiver from the switch hook of a substation, whereby the accidental failure to return the talking key to normal aposition. at the master station will again 0 is again placed. upon its hook.

the sub-station when the receiver 10. In an intercommunicating telephone" system, a plurality of sub-stations 'a plurality of master stations, means or connecting the transmitters andreceivers of ter station in a talking circuit with a trans initter of a sub-station or another mastersta tion and estabhshmg a similar'connection between the transmitter of a masterstation and the receiver of a sub-station or another master station, and means for always giving a visual indication at a station of a. call from another station if one of the two stations is a master station. a

-12. In an intercommunicating telephone system, a plurality of sub-stations, a -plu rality of master stations, means for connect ing the transmittersand receivers of two sub-stations in a talking circuit, separate means for connecting the receiver of a master station in a talking circuit witha transmitter of a sub-station or another master station and establishing between the transmitter of a' master station and the receiverof a sub-station or another a similar connection i master station, and means for always 'ving a visual indication at a station of a ,ca from another station if one ofthe twostation s is a master station and for giving an audible sig- 7 nal if the station called is not busy. a

13. In an mtercommunicating telephone system, a plurality of s'ub-stationsand aplurality of master stations, a plurality ofta'lk-u ing keys at each station, one for each station; I

of the system, aseparate calling keygat each sub-station, calling circuits between the talk. ,7

ing and calling keys of a sub-station and the talking keys of the mast'e calling circuits between th a.

g key-" ie the master stations aturing-circ its tween the talking keys of the several tions,- said talking circuits and callin circuits from a master station simultaneously.

- y 14. In an intercommunicatingj telephonew;

i stationsyother' 12o osed 1 system, a plurality of substations and spl -a ing keys at each station, one for each station rality of master stations, a pluralityoftalk of the system, a separate calling key at each substation, calling circuitsbetweenthe talking and callin keys of a sub-station and ,g keyso themaster stationa, other lee 

